philipp_1966 ============ H\. R\. Philipp, "Optical transitions in crystalline and fused quartz", Solid State Commun\. 4, 73 \(1966\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1016/0038\-1098\(66\)90109\-8 `__ **Source kind:** measurement **Recorded technique:** Reflectance of non\-polarized light at near\-normal incidence, 8\-26 eV, on a Z\-cut alpha\-quartz crystal, compared with fused silica; below about 7 eV the reflectance was computed from index\-of\-refraction data \(footnote 2\: the American Institute of Physics Handbook, 2nd ed\., p\. 24\)\. Kramers\-Kronig analysis \(Philipp and Taft, Phys\. Rev\. 136, A1445 \(1964\)\) of the crystal's reflectance for eps\_1 and eps\_2 \(p\. 73\)\. **Materials in structured entries:** None recorded. **Dataset quantities:** None recorded. **Contents:** 0 datasets; 0 formulas. Curation notes -------------- Journal pages 73\-75 = pdf pages 1\-3 \(a two\-page note; p\. 75 is references 3\-10 and the German abstract\)\. The library has no extracted tables and the note has none\: the pages were read from the page images \(2026\-09\-27\)\. Identity checked against the first page\. NOTHING IS TRANSCRIBED\: the optical data are in figures only, and the note prints no peak energies, band gap or eps values at the peaks\. WHAT THE NOTE HOLDS \(figures, not digitised\)\: \- Fig\. 1 \(p\. 73\)\: reflectance \(per cent, 0\-30\) against photon energy \(0\-26 eV\) of crystalline quartz \('SiO2 \(crystal\)'\) and fused quartz \('SiO2 \(fused\)'\); 'For clarity, the values for fused quartz have been lowered by 5 per cent' \(caption\)\. The curves show 'a series of relatively sharp peaks which are slightly broadened for the amorphous material' \(p\. 73\)\. \- Fig\. 2 \(p\. 74\)\: eps\_1 and eps\_2 of crystalline quartz on a logarithmic axis \(0\.1\-10\) against photon energy \(0\-20 eV\), from the Kramers\-Kronig analysis; 'The curves for fused SiO2 are very similar and for reasons of clarity are not shown here' \(p\. 73\)\. TEXT \(no vocabulary quantity; notes only\)\: \- The spectrum can be represented 'by a series of four oscillators, which become lifetime broadened as one goes to higher energies, followed above ~20 eV by a region of relatively smooth absorption possibly associated with transitions from the deeper lying L\-shell electrons of oxygen' \(p\. 73\); the oscillator energies are not given\. \- Both forms 'become opaque' above about 8 eV \(p\. 73\)\: a qualitative statement, not a band\-gap determination\. \- Eqs\. \(1\)\-\(2\) \(p\. 74\)\: the classical oscillator polarizability, eps\_1\(omega\) \- 1 = 4 pi alpha = 4 pi rho \(sum\_j f\_j e^2/\(4 pi^2 m\) \(omega\_j^2 \- omega^2\)/\(\(omega\_j^2 \- omega^2\)^2 \+ Gamma^2 omega^2\) \+ A\), with f\_j the oscillators per unit mass and rho A the core contribution; the local\-field correction is neglected \(footnote 6\)\. No parameters are given, so it is not recorded as a formula\. \- 'The density ratio 2\.65/2\.20 = 1\.2 of crystalline compared to fused quartz'; \[eps\_1\(omega\) \- 1\]/rho at hbar omega = 2 eV is 0\.52 \(crystalline\) and 0\.51 \(fused\) \(units not printed; cm^3/g with the densities in g/cm^3\), and \(alpha/rho\)\_crystal / \(alpha/rho\)\_fused = 1\.02 'throughout most of the transparent range' \(p\. 74\)\. These come, presumably, from the handbook index data of footnote 2, not from new measurements\. \(With rho = 2\.65, 0\.52 gives eps\_1 = 2\.38, n = 1\.542, the ordinary index of quartz near 620 nm; with 2\.20, 0\.51 gives n = 1\.457, fused silica's\.\) \- The Si\-O distance, about 1\.62 A \(p\. 74, from Wyckoff\)\. LATER USE\. Philipp's J\. Phys\. Chem\. Solids 32, 1935 \(1971\) \(philipp\_1971\) shows the same reflectance \(its Fig\. 1, same caption and offset\) with the Kramers\-Kronig results of both forms; Palik's handbook chapter \(philipp\_1985, Table X, tags \[9\] and \[9, 10\]\) is the first tabulation of these results, and cites this note\. Lamy \(lamy\_1977\) finds Philipp's fused\-quartz peaks narrower than his own, especially near 1220 A \(10\.2 eV\), his crystal\-quartz reflectance in good agreement, and his own crystal eps\_1 larger by typically 0\.2 than Fig\. 2's\. Rife and Osantowski \(rife\_1980\) cite it for the 720 A peak\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- No datasets are recorded. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.